A very useful style of single-hole mount fastener for cabinets or other similar uses has a non-rotatable latch housing, mounted in a swinging door, that carries a reciprocating spring-loaded pawl that fastens against the edge of a metal keeper installed on the inside of the cabinet frame. As the door is closed, the pawl, which slidingly operates against an extension spring in a perpendicular direction to the direction of the mounted housing, presents a cam surface to the keeper. As the door moves closer to its fully closed position, the cam surface of the pawl slides to its outer end, in opposition to the spring, until it clears the keeper and the stored-up spring force then moves it back out to an extended and latched position with the pawl now presenting a non-cam surface to the keeper. Various types of opening actions, such as twisting a knob or a key or pushing a knob or other activation means, provide retraction of the pawl to ensure clearance of the non-cam surface past the keeper, to unfasten the latch and allow the door to be pulled open away from the frame.
A disadvantage of this type of fastener, whether key-operated or knob-operated, is that there is no positive-feel position showing when the latch is fully open, and therefore when the door can be pulled open, and the operator must remember to provide an opening force - thereby pulling the pawl away from the keeper - at the moment the outer end of the upper or non-cam surface clears the edge of the keeper. Otherwise, the possibility exists that an opening force used by the operator will jam the pawl against the keeper, thereby causing damage to either, or both, the keeper or the pawl.
Another disadvantage to the slam-action latch that uses a non-key push-button as the latch actuator is that there is no structure, other than the push-button knob, which can be pulled on to open the door. Once the push-button knob is depressed, the latch becomes flush-mounted, and presents no object for the user to grasp.